Champagne
People often call any sparkling wine Champagne, but in reality, only sparkling wine made in the Champagne region of France can be called Champagne. It must be made from Pinot Noir (ablanc de noirs is a Champagne made predominantly from Pinot Noir grapes), Pinot Meunier, or Chardonnay (blanc de blanc is made from Chardonnay), and is most often a blend of all three.
Champagne is produced by méthode champenoise. This method is said to have been fortuitously invented by a certain monk named Dom Perignon and refined by the widow (veuve) Cliquot. Both of these names should be familiar to any Champagne enthusiast (or even non-enthusiast) because they are still the two most famed houses of Champagne.
Méthod champenoise involves adding more yeast and sugar to a base of wine, then bottling the wine for a second fermentation. During this process, the wine sits on the dying yeast and sediment that forms, called the lees, and the bottle is gradually tipped and spun so that all the lees collect in the neck of the bottle. The bottle is then flash-frozen, the lees are popped out, and the bottle is sealed again, to be popped once more at a wedding, or engagement, or housewarming, or some other important occasion.
Due to the lengthy process of sitting on the lees, Champagne takes on richness and complexity and its signature biscuit-y or yeasty notes. And, while some styles of Champagne are crisp with notes of lemon, apples, and flint, fine champagnes frequently become bold with flavors of toasted brioche, roasted fruit, and toffee.
Prosecco
Prosecco is Italy’s most widely known sparkling wine. For many years, it played a second fiddle to Champagne because much of the Prosecco available just wasn’t good. But fine Prosecco’s have become more widely available, and it now runs neck and neck with Champagne for popularity.
Prosecco is made in the Veneto region of Italy (the same region that gave us the glorious Aperol spritz, from a varietal of grape called Glera. The production method of Prosecco is notably different from Champagne or Cava in that the secondary fermentation that gives bubbly wine its fizz happens in steel tanks rather than in bottles. This impacts the flavor notably, making it lighter and less yeasty. Prosecco can tend to be a little sweeter than Champagne or Cava, with bigger loser bubbles and buoyant flavors of apple, pear, lemon rind, light flowers, and even tropical fruit.
Cava
Cava is Spain’s most notable contribution to the world of sparkling wine, and a most excellent contribution it is. Cava is usually made with a few grape varietals that you probably haven’t ever heard of—Macabeu, Parellada, and Xarello—though it can also be made from Chardonnay or Pinot grapes.
Though you’ll mostly see Cava at a price point similar to Prosecco, it’s actually more similar to Champagne in character and production. Like Champagne, the effervescence-producing secondary fermentation happens in the bottle (rather than a tank), but outside of the French region, the method cannot be called méthode champenoise and is instead known as méthode traditionnelle. (One reason—besides the name recognition and global demand that inflates Champagne’s price point—that cava is more reasonably priced is that the Spanish have mechanized the process of tirage, the rotating and tipping of the bottles during the secondary fermentation; in France, on the other hand, it is often still done by hand.)